Summary of Union Carbide’s 1964 study on gas centrifuge technology’s effect on nuclear proliferation. The summary provides Union Carbide’s estimations for how long countries of varying industrial capability would take to develop a nuclear weapon, which was redacted in the original document.

The development of the gas centrifuge method, according to this report, would make production of U-235 (and by extension, nuclear weapons) possible for as many as 20-30 foreign countries. The U.S. is thus forced to consider its strategy for how to limit proliferation despite this new, cheap technology.

US Atomic Energy Commission classification director C. L. Marshall explains to international affairs director A. A. Wells that the design for the gas centrifuge must be classified for fear of providing an “unfriendly nation” a low-energy consuming method for “the separation of heavy isotopes…an important part of a [nuclear] weapons program.”